/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#ifndef itkNumericTraitsStdVector_h
#define itkNumericTraitsStdVector_h

#include "itkNumericTraits.h"
#include <vector>

// This work is part of the National Alliance for Medical Image Computing
// (NAMIC), funded by the National Institutes of Health through the NIH Roadmap
// for Medical Research, Grant U54 EB005149.

namespace itk
{
/**
 * \brief Define numeric traits for std::vector.
 * \tparam T Component type of std::vector
 *
 * We provide here a generic implementation based on creating types of
 * std::vector whose components are the types of the NumericTraits from
 * the original std::vector components. This implementation require
 * support for partial specializations, since it is based on the
 * concept that:
 *   NumericTraits<std::vector< T > >  is defined piecewise by
 *   std::vector< NumericTraits< T > >
 *
 * \note The Zero(), One(), min() and max() methods here take
 * references to a pixel as input.  This is due to the fact that the
 * length of the std::vector is not known until
 * run-time. Since the most common use of Zero and One is for
 * comparison purposes or initialization of sums etc, this might just
 * as easily be re-written with a pixel passed in as a reference and
 * the length is inferred from this pixel.
 *
 * \sa NumericTraits
 * \ingroup DataRepresentation
 * \ingroup ITKCommon
 */
template< typename T >
class NumericTraits< std::vector< T > >
{
public:

  typedef typename NumericTraits< T >::AbsType        ElementAbsType;
  typedef typename NumericTraits< T >::AccumulateType ElementAccumulateType;
  typedef typename NumericTraits< T >::FloatType      ElementFloatType;
  typedef typename NumericTraits< T >::PrintType      ElementPrintType;
  typedef typename NumericTraits< T >::RealType       ElementRealType;

  /** Return the type of the native component type. */
  typedef T ValueType;

  typedef std::vector< T > Self;

  /** Unsigned component type */
  typedef std::vector< ElementAbsType > AbsType;

  /** Accumulation of addition and multiplication. */
  typedef std::vector< ElementAccumulateType > AccumulateType;

  /** Typedef for operations that use floating point instead of real precision
    */
  typedef std::vector< ElementFloatType > FloatType;

  // TODO: this won't really print well, at least not without defining an operator
  // to push to a stream.
  /** Return the type that can be printed. */
  typedef std::vector< ElementPrintType > PrintType;

  /** Type for real-valued scalar operations. */
  typedef std::vector< ElementRealType > RealType;

  /** Type for real-valued scalar operations. */
  typedef ElementRealType ScalarRealType;

  /** Measurement vector type */
  typedef Self MeasurementVectorType;

  /** Component wise defined element
   *
   * \note minimum value for floating pointer types is defined as
   * minimum positive normalize value.
   */
  static const Self max(const Self & a)
  {
    Self b( a.Size(), NumericTraits< T >::max() );
    return b;
  }

  static const Self min(const Self & a)
  {
    Self b( a.Size(), NumericTraits< T >::min() );
    return b;
  }

  static const Self ZeroValue(const Self  & a)
  {
    Self b( a.Size(), NumericTraits< T >::ZeroValue() );
    return b;
  }

  static const Self OneValue(const Self & a)
  {
    Self b( a.Size(), NumericTraits< T >::OneValue() );
    return b;
  }

  static const Self NonpositiveMin(const Self & a)
  {
    Self b( a.Size(), NumericTraits< T >::NonpositiveMin() );
    return b;
  }

  /** Resize the input vector to the specified size */
  static void SetLength(std::vector< T > & m, const unsigned int s)
  {
    // since std::vector often holds types that have no NumericTraits::ZeroValue(),
    // allow resize() to call the type's default constructor
    m.clear();
    m.resize(s);
  }

  /** Return the size of the vector. */
  static unsigned int GetLength(const std::vector< T > & m)
  {
    return m.size();
  }

  static void AssignToArray( const Self & v, MeasurementVectorType & mv )
  {
    mv = v;
  }

  template<typename TArray>
  static void AssignToArray( const Self & v, TArray & mv )
  {
    for( unsigned int i=0; i<GetLength(v); i++ )
      {
      mv[i] = v[i];
      }
  }

};
} // end namespace itk

#endif // itkNumericTraitsStdVector_h
